| 摘要 |
PURPOSE:To hold lens in a state of less aberration by beveling the circumferential edge of the 2nd concave surface of a lens on the opposite side to an object and allowing the annular contacting part of the 2nd surface to abut on a body- attached surface in a lens barrel. CONSTITUTION:The 2nd surface 10r is a concave surface, so the boundary part between the 2nd surface 10r and beveled part 11 is formed into an annular and linear contacting part 14 for contacting the body-attached surface 13 of the lens barrel 12. This surface 13 for contacting and holding the lens 10 is formed nearly at right angles to an optical axis O and said linear contacting part 14 of the lens 10 contacts the surface uniformly. Consequently, if the lens 10 moves, it becomes parallel to the body-attached surface 13 crossing the optical axis O at right angles, so the 1st surface 10f is concave and even parallel eccentricity due to movement less causes a circumferential out-of-focus state. |
